Many small children have problems with nightmares. Recent studies done

Question

Many small children have problems with nightmares. Recent studies done by psychologists show that these nightmares can be reduced by letting the children fall asleep with the lights on. Two groups of children took part in such a study. The group that fell asleep with the lights off indicated that they had more nightmares than the group that fell asleep with the lights on. 
Which of the following questions would be most useful for evaluating the conclusion?

(A) Are nightmares more prevalent among children than among adults?
(B) Did teenagers who fell asleep with the lights on have the same number of nightmares as before?
(C) Are children who play violent computer games more likely to have nightmares?
(D) Did children who previously had problems with nightmares show a markedly decreased incidence of nightmares after five months of falling asleep with the lights on?
(E) Do children with a high level of self-esteem have fewer problems with nightmares than children with average levels of self-esteem?

amansoni5 · Answer

Can someone explain the answer for this question?

siddhantvarma · Answer

Conclusion: Falling asleep with lights on can reduce nightmares for Children.
To support the conclusion, there was a study conducted:
Two groups of children were studied:
 
 Group 1 (lights  off ) =>  more nightmares  
 Group 2 (lights  on ) =>  fewer nightmares

To evaluate the conclusion, we need to know if  turning on the lights  was the  cause  of the  reduction in nightmares .

(A)  Are nightmares more prevalent among children than among adults?
Adults are out of the scope of this study as it focuses on Children, eliminate A since it's irrelevant ❌

(B)  Did teenagers who fell asleep with the lights on have the same number of nightmares as before?
This may be a tricky one but we can also eliminate it based on "teenagers". The argument focuses on children and teenagers may be subset of children and may not be representative of the entire data set. The passage also clearly mentions  small children  so teenagers may even not be relevant here => Eliminate ❌

(C)  Are children who play violent computer games more likely to have nightmares?
 This doesn't help evaluate the effect of lights. We're not interested in evaluating the effect of computer games => Irrelevant, eliminate ❌

(D)  Did children who previously had problems with nightmares show a markedly decreased incidence of nightmares after five months of falling asleep with the lights on?
 This directly checks if the change in  lighting condition  led to  fewer nightmares , which is what the argument concludes. If children who had nightmares previously, saw a reduction due to lights on, we know sleeping with lights on worked. If children who had nightmares previously didn't see a reduction due to lights on, we know it didn't work. So this answer choice helps us evaluate the argument, if lights on really helped with nightmares or not => Keep ✅

(E)  Do children with a high level of self-esteem have fewer problems with nightmares than children with average levels of self-esteem?
Again, self-esteem is out of scope here, we're interested in the effect of light on nightmares => Eliminate ❌

Correct Answer: (D)

Many small children have problems with nightmares. Recent studies done

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Many small children have problems with nightmares. Recent studies done

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